Brake



BRAKE Filed July 22, 1940 2 Sheets-Sheet 2 Afforney Patented Oct. 14, 1941 nnsxn Karl many Rabe, Stuttgart, Germany, assignor to 1'. ing. 11. c. F. Porsche K.-G., Stuttgart- Zuflenhausen, Germany,

a company oi Ger- Application July 22,1940. Serial No. 346,722 In Germany July 14, 1939 8 Claims. (oi. 188-795) This invention relates to improvements in a brake, and more for use with power vehicles.

An object oi brake having a struction.

Another object of this invention is to provide a sturdy, self-adjusting vehicle brake at a lower cost than heretofore possible.

Still another object of this invention is the particularly to a brake adapted I this invention is to. provide a simple. self-adjusting shoe con- Rollers I1 and it are ireelyrotatably mounted upon the respective pivot'bolts i2 and I 6 and are adapted to run along'respective track pro- Jections i9 and 20 on the brake supporting plate 6. The shoes are held in place by means or a leaf spring 22 attached at its center to the brake supporting plate 6 by suitable meanssuch as a cotter-pin 2!, the spring 22 serving to press the provision or a brake which will at all times prcvide a good braking action with a minimum of A wear on the brake linings.

A further object of this invention is to provide an improvedbrake construction in which the. danger or undesirable locking is substantially avoided.

A more specific object of this invention is to provide a brake in which the brake shoes are always moved in a substantially radial direction, both for the purpose of adjustment and during the braking operation. I

' These and other features, capabilities and advantages of th invention will appear from the subjoined detail description of one embodiment and a modification thereof, illustrated in the accompanying drawings, in which:

Fig. 1 is a plan view of a brake formed in acshoes.

[and 44, slotted at their extremities, and movable in an abutmenthousin'g 4B. A threaded bolt 48 cordance with the present invention, with the brake drum removed; a

, Fig. 2 is a horizontal cross-sectional view along theline II-II 0i"Fig'.1; Fig. 3 is a horizontal cross-sectional view along thelineIII-IIIoiFig.l:and' 1 Fig. 4 is a partial horizontal cross-sectional rollers 11 and I8 along the guidingtracks i9 and 20. Return springs 23 and 2'4'hold the opposit ends of the brake shoes in a normally released position away trom the brake drum 25,

indicated by dotted lines in Fig. 1.

In their released position, the upper ends 01' the brake shoes are'held suspended by means or pins 26 and 2'! engaging the walls or notches 28 and 29 formed inthe projectionson the upper end of the brake supporting plate 6. The pins 26-and21 are preferably attached, in a manner.

to be hereinafter described, in the bridging members 4| and 42 between the ends oi the brake At the lower ends orthe brake shoes, the abutment 5 therefor is pret erablymade adjustable in sucha manner as to eii'ect a substantially radially directed adiustment. For this purpose, there are provided a-pair oi slidabie members 43 is provided with a conically shaped-key 41 resting against the inner ends of the slidable members 43 and 44. The lower ends or the bridging members 4! and 42 respectively attached to the shoes I and. 2 are formed with their surfaces view con-spending to Fig. 3, illustrating a 'modi- I lied constructional arrangement.

The brakeconstruction as illustrated in Figs. 1, 2 and 3, includes two shoes I, 2, having respective linings 8 and 4.. The lower ends of the shoes are, pressedagainst an abutment I upon the b of the shoes are pressed against a suitable spreading device for the actuation of the brake, This spreading device may consist of anangular crank member 1 on whose one arm 8 the brake cable I is attached, and which is pivoted about rake-supportingpiate i, while the upper ends curved in an approximately radial direction and mounted within the slot at the ends of theslidable members 43 and 44. It will be apparent that upon adjustment of the key member 41 to move the slidable members 42 and 44' simulta- 'neously-outwardlyor inwardly, an adjustment of the lower ends of the brak shoes will be eiiected, and because 01' the curved surfaces 49 and ill upon the ends of bri sing members 4! a point II to the shoe' 2 bymeans-oi a pivot bolt l2. The other arm ll of the crank member I is pivoted to .a connecting member l4 bymeans of a pivot pin II, while the connecting member I4,

in turn, is pivotally interconnected with the shoe l by means of the bolt i8. By reason of this ar rangement the spreading device; is solely supported by and between the shoes i and 2. a

and 42., this adjustment may take place-in a substantially radial direction.

A relatively free movement of the upper ends by means orthe coni of the shoes is permitted struction inaccordance with this invention. In

this case the ends of the l s n'g members 4| and 42 are formed with cut-out portions ii' and 52 into which the end or the spreading device may iit. A guidance or the spreading device relatively to the brake shoe is brought about by the fact that theouter endsoi the pivot pins l2 and I! are slotted to receive the projecting ends the brake axis.

2 of the bridging members 4| and 42, so that a movement of .the spreading device up to the These pins are preferably provided with suitable collars 53 and54 to hold them in place in one direction, but through springs 55 and 59 held on the pins by suitable means such as a slotted disc,

1 are said pins seated tiltably in openings u' and 42', enlarged at one end to permit the tilting movement, in the ends of the respective bridging members 4| and 42 of the brake shoes I andl. This slightly yieldable engagement between the ends the brake shoes and thenotches formedv inthe extension upon the brake supporting plate .point at which the pins bear against the ends The principles of this invention may be applied to brakes having external shoes as well as to brakes having internal shoes. Furthermore, the particular construction of the shoe spreading device is of no importance with respect to this invention, and other changes may be made in detail, as will be at once obvious to those skilled in this art.

6, permits a yielding movement of the pins 26 and 21 along the walls oi-thenotches 28 and 29.

By reason of the above described construction I it will .be noted that radial movement of both ends of each brake shoe, and of each brake shoe as'a whole is permitted. The sliding contact of;

"the lower ends of the brake shoe with the abutment permits movement or these brake shoe ends in a radial direction, while movement of the pins 29, 21 in the upper'ends of the brake shoe, along the surface. of notches 28 and 29, respectively, permits radial movement at-these ends. At the same time, however, the sprung action of the pins 26, 21, insuresv that the upper ends of the spreading device is released. s

The construction described. above 'wili be seen brake shoewill always be centered when the to carryout, the objects primarily stated. If the brake shoes are worn or are inaccurate, they can 'be adjusted by movement of the conically shaped.

key 4T sothat the linings will be iniull contact with thebrake drum. Thus, any inaccuracies in manuifacture may be readily compensated for by I this adjusting action and special care during the manufacturing need not be'exercised. "Now if the brake drum 25 turns, tor-example, in the di-- rection oi; the-arrow R, the shoes themselves can then shift-still further until they are in that position giving the bst braking action, this shift-- ing being permissible since the bolts 26 and 21 are formed yieldably and' can move along the walls of'the notches it-and 29, respectively. The

. shoes will in thiscase then produce a-better brakingaction without the shoe 2 ever locking. After the braking operation the springs and 56 will move the=bolts 26 and 21 to re-center the shoes.

In Fig. 4 isillustrated a modification of the' brake shoeadjusting device. In this case, the slot formed in the ends of the members 43 and 44 is made definitely larger than the inserted ends of Accordingly, while I have herein shown and described only certain embodiments and certain features'of my present invention, itiis to be understood that they are to be regarded merely as illustrative and that I do not intend to limit myself thereto except as may be required by the following claims. I

'I claim: a

1. In a brake, in combination, a supporting plate, a pair of brake shoes, an adjustable abutment fixed on said plate; means for pressing one end of each of said shoes against said abutment, means for' adiusting said abutment and moving said ends in a substantially radial direction, a shoe-spreading device supported between the other ends of said shoes, and stops on the otherendsof said shoes, said'brake plate being provided with 'concave recesses so positioned as to receive said stops in the released position of said stops are slidable, whereby the said other ends of said brake shoes are shiftable in a substantially radial direction upon actuation of said spreading device.

2. The combination according to claim 1, in which the said stops are formed yieldable in a substantially radial'jdirection. v

3. The combination according to claim 1, in which said stops are formed yieldable in a substantially radial direction, and spring means for opposing movement of said stops.

i. The combination according to claim 1, in which said stops are tiltably mounted in said other ends of the shoes.

'5. The combination according to claim 1, in which said stops are formed by studs extending through the shoes, having a collar on the side of opposite sides of the shoes.-

which the one ends of said shoes are provided with a substantially convexly curved contacting surfzzce pressing against said adjustable'abutmen v 7. The combination according to claim 1, in

55 combination with means for dampening the ad the bridging member 4| and 42, and dampening means such as small leaf springs 51 and 59 are attached to the projecting ends of thebridging members and bear against the inner sides of the surrounding slot.- By reason of this construction, after the brakes have been once adjusted they. will .be held in this position and thus give the proper braking action after the brakes have been released. a a

justment of the one end of each of said shoes'by said adjustable abutment. I

8. The combination according to claim 1, in

- in which said abutment includes a pair of transa notch at their free ends, and the one ends oi said shoes are provided with portions extending inwardly into said notches, in combination with a-p'air of leaf springs mounted on opposite sides of each of said inwardly extending portions and pressing outwardly against the inner surfaces of the surrounding notch.

6. The combination according to claim 1, in

versely adjustable members each provided with 

